<< Chapter < Page Chapter >> Page >

The statement containing the cast operator is shown below for convenient viewing.

myIntVar = (int)myDoubleVar;

Syntax of a cast operator

The cast operator consists of the name of a type contained within a pair of matching parentheses.

A unary operator

The cast operator always appears to the left of an expression whose type is being converted to the type specified by the cast operator.

Assuming responsibility for potential problems

When dealing with primitive types, the cast operator is used to notify the compiler that the programmer is willing to assume the risk of a possible loss ofprecision in a narrowing conversion.

No loss of precision here

In this case, there was no loss in precision, but that was only because the value stored in the double variable was within the allowable value range for an int .

In fact, it was the largest positive value that can be stored in the type int . Had it been any larger, a loss of precision would have occurred.

More on this later ...

I will have quite a bit more to say about the cast operator in future modules. I will also have more to say about the use of the assignmentoperator in conjunction with the non-primitive types.

Back to Question 4

Answer 3

A. Compiler Error

Explanation 3

Conversion from double to int is not automatic

This program attempts to assign a value of type double to a variable of type int .

Even though we know that the specific double value involved would fit in the int variable with no loss of precision, the conversion from double to int is not a widening conversion.

This is a narrowing conversion

In fact, it is a narrowing conversion because the allowable value range for an int is less than the allowable value range for a double .

The conversion is not allowed by the compiler. The following compiler error occurs under JDK 1.3:

Ap012.java:16: possible loss of precision found : doublerequired: int myIntVar = myDoubleVar myIntVar = myDoubleVar;

Back to Question 3

Answer 2

C. 2.147483647E9

Explanation 2

Declare a double

The method named doAsg first declares a local variable of type double named myDoubleVar without providing an initial value.

Declare and initialize an int

Then it declares an int variable named myIntVar and initializes its value to the integer value 2147483647 (you learned about Integer.MAX_VALUE in an earlier module) .

Assign the int to the double

Following this, the method assigns contents of the int variable to the double variable.

An assignment compatible conversion

This is an assignment compatible conversion. In particular, the integer value of 2147483647 is automatically converted to a double value and stored in the double variable.

The double representation of that value is what appears on the screen later when the value of myDoubleVar is displayed.

What is an assignment compatible conversion?

An assignment compatible conversion for the primitive types occurs when the required conversion is a widening conversion.

What is a widening conversion?

A widening conversion occurs when the allowable value range of the type of the left operand of the assignment operator is greater than the allowable valuerange of the right operand of the assignment operator.

Questions & Answers

start new n questions too
Emmaunella Reply
summarize halerambos & holbon
David Reply
the Three stages of Auguste Comte
Clementina Reply
what are agents of socialization
Antonio Reply
sociology of education
Nuhu Reply
definition of sociology of education
Nuhu
definition of sociology of education
Emmaunella
what is culture
Abdulrahim Reply
shared beliefs, values, and practices
AI-Robot
What are the two type of scientific method
ogunniran Reply
I'm willing to join you
Aceng Reply
what are the scientific method of sociology
Man
what is socialization
ogunniran Reply
the process wherein people come to understand societal norms and expectations, to accept society's beliefs, and to be aware of societal values
AI-Robot
scientific method in doing research
ogunniran
defimition of sickness in afica
Anita
Cosmology
ogunniran
Hmmm
ogunniran
list and explain the terms that found in society
REMMY Reply
list and explain the terms that found in society
Mukhtar
what are the agents of socialization
Antonio
Family Peer group Institution
Abdulwajud
I mean the definition
Antonio
ways of perceived deviance indifferent society
Naomi Reply
reasons of joining groups
SAM
to bring development to the nation at large
Hyellafiya
entails of consultative and consensus building from others
Gadama
World first Sociologist?
Abu
What is evolutionary model
Muhammad Reply
Evolution models refer to mathematical and computational representations of the processes involved in biological evolution. These models aim to simulate and understand how species change over time through mechanisms such as natural selection, genetic drift, and mutation. Evolutionary models can be u
faruk
what are the modern trends in religious behaviours
Selekeye Reply
what are social norms
Daniel Reply
shared standards of acceptable behavior by the group or appropriate behavior in a particular institution or those behaviors that are acceptable in a society
Lucius
that is how i understood it
Lucius
examples of societal norms
Diamond
Discuss the characteristics of the research located within positivist and the interpretivist paradigm
Tariro Reply
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Object-oriented programming (oop) with java. OpenStax CNX. Jun 29, 2016 Download for free at https://legacy.cnx.org/content/col11441/1.201
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Object-oriented programming (oop) with java' conversation and receive update notifications?

Ask